1. Field of the Invention
The present invention relates to a method for transmitting/receiving image data using a mobile communication terminal, and more particularly to a method for transmitting both image data and voice data in a group communication system capable of performing a push-to-talk function.
2. Discussion of the Related Art
Generally, a group communication system well known to the art as a point-to-multipoint (PTM) communication system or a push-to-talk (PTT) communication system is indicative of a system for allowing only one user, who has an exclusive transmission right during a predetermined time, to transmit desired information to other network members. Typically, the above-mentioned group communication system includes a plurality of transceivers, and the transceivers are tuned to the same frequency (i.e., the same channel). If a user, who has a transmission right and desires to send his or her voice signal to a called party, presses a PTT switch 110 positioned at one side of a mobile terminal 100 shown in FIG. 1, the mobile terminal 100 transmits the voice signal to the called party. If the user takes his or her finger off of the button 110, the mobile terminal 100 enters a reception mode. If there is a method for determining which one of persons will transmit the next message, predetermined users share the same frequency with one another.
FIG. 2 is a conceptual diagram illustrating a group communication system. Referring to FIG. 2, the group communication system includes a plurality of wireless telephones 211, 212, and 213, first and second base stations 221 and 222, and an Internet-, Intranet-, or Extranet server 230. The first wireless telephone 211 and the second wireless telephones 212 wirelessly communicate with the first base station 221. The first base station 221 communicates with the Internet-, Intranet- or Extranet server 230 over the Internet, the Intranet, or the Extranet. In fact, a large number of routers and other devices are included in the group communication system shown in FIG. 2. The third wireless telephone 213 wirelessly communicates with the second base station 222. The second base station 222 communicates with the Internet-, Intranet, or Extranet server 230 over the Internet, Intranet, or Extranet.
A communication scheme based on the above-mentioned group communication system provides a caller user and a called party with only a voice exchange service. Therefore, if there is a meeting of a certain group at a specific meeting place, the caller user may have difficulty in explaining the meeting place to the called party. In order to verbally explain the above-mentioned meeting place using the PTT service, most users must verbally explain the meeting place to their called parties several times.
Therefore, some users may frequently transmit a rough map including position information of the meeting place to their called parties. In this case, if raw data of the rough map image is transmitted to the called parties without any change, large amounts of data are created. Also, if a group communication caller user transmits an image configured in the form of a file, no problem occurs in the image transmission. Otherwise, if an image is drawn on a liquid crystal display (LCD) in real time, a changed part drawn by a caller user's handling must be checked by a specific device in real time, such that the specific device may have a complicated structure. As a result, an amount of load applied to a network is greatly increased, resulting in deterioration of call quality.